Uli Plank wrote:IMHO the lenses used are more important to match them than anything else. As long as you don't need off speeds and deliver 1080p, they are damn close, but watch out for moiré on the BMCC.
Very much agreed. I've been doing some very detailed testing of BMCC vs. RED EPIC DRAGON, and the Voigtländer lenses on the BMCC are really giving the Canon L glass on the DRAGON a run for their money. Once I get Cine glass for the DRAGON, I expect it will be much less of a contest. That said...
Using identical apertures and frame rates (therefore the same light hitting the sensors) the DRAGON really does see 3 stops deeper into the highlights. But the BMCC seems to have a stop more sensitivity before noise starts to pick up. The simple interpretation there would be to expose the DRAGON +1 stop, giving equal performance before noise picks up and still benefit from 2 stops more highlight protection. But my testing suggests that actually the noise of the DRAGON is so organic (for lack of better term), it can actually be pushed down in post very, very nicely. The noise of the BMCC is not nearly as easily discharged. Notably, the BMCC noise tends to posterize in blotches, compared with the DRAGON, which remains granular all the way. The EPIC does not have the extra DR of the DRAGON, but I believe it does have a much better noise pattern in the shadows.
Looking at the images of both in Resolve, the gamma curves and LUTs you start with can convince you that there is as much as a +/- 1.5 stop difference in exposure at the same ISO/aperture/frame rate settings. (Shoot a DSC Labs CamAlign waveform chart and you'll see differences in where the "X" sits, low, high, and in the middle.) Which means that you really should decide what your grading start point is going to be and then expose appropriately so that those two starting points don't diverge too much. RC3/RG3 looks very different than BMD Film->REC 709. RED RAW -> Arri CineLog -> REC 709 also looks different than BMD Film -> REC 709, and not only in terms of how reds, greens, and blues look. They are different in terms of where they place mid-tones, shadows, and highlights. Davinci Resolve is a powerful tool for getting the cameras to agree, and it doesn't take long, but you don't want to find you underexposed one camera compared to the other by 1.5 stops due to an unfortunate choice of base gamma and one-light correction. In my tests, 80% of the time it was the EPIC that needed more base exposure to come to agreement with the BMCC, but 20% of the time it was the other way around. If you don't have time for a test, you could factor the probabilities and over-expose the RED by 1 stop, which would give you an 80% chance of being within 1/2 stop of perfect. But also a 20% chance of being off by more than 2 stops.
If you use the same lenses on both, if you expose properly so that your one-light corrections effectively show that your base exposures agree, and if you don't make the camera's weakest point the principal subject of the image, you will do great. Unless of course you trigger moire on the BMCC. The best solution to that problem is coverage: always have at least one other shot that can cover whatever was ruined by moire!